Legless Amphibia look as snakes or large hearts. Scientists allocated them in separate group. One more name of legless Amphibia – a chervyaga.
Small and poorly studied
Legless are considered as the smallest group of Amphibia. It includes only about 200 types. Bright representatives of this group are a chervyaga, rybozmy.
Generally legless live in the damp soil therefore they not so often catch sight. They began to be studied at the beginning of the 18th century. At that time researchers took them for snakes.
By closer consideration it became clear that they completely different on anybody not similar. Zoologists still do not know for sure how long there live these animals when they for the first time can have posterity how far migrate, etc.
Sizes
Some of legless Amphibia only several centimeters in length, others grow to meter. The largest representative of group – a giant chervyaga. It reaches in length of 117 cm. The giant chervyaga lives in Colombia at the height up to 1150 m above sea level.
Origin
Scientists believe that chervyag, frogs and salamanders have the uniform ancestor living about 275 million years ago. At chervyag strong similarity to a salamander.
Biologists think that ancient salamanders began to rummage in the soil and a sheet laying millions years ago to hide from enemies and also in search of livelihood. Being more and more underground, they evolved. Gradually legs disappeared, and the body became longer. On it ring interceptions are noticeable: in these furrows under skin the smallest bone scales – the remains of an armor of ancient amphibians are hidden. The skull became massive and strong, allowing an animal to ram the soil. It is remarkable that in it the muscles not characteristic for one living organism are found. Scientists call them a nature riddle.
Eyes stopped being the necessary body and grew with the thick layer of skin preserving against dirt, damages and allowing to distinguish only light and darkness. But amphibious had peculiar short moustaches helping to find in the dark food and to find chemicals.
Under water and on the Earth's surface of a chervyaga can move, it is serpentine being bent. Underground legless move by means of a wave of muscular contractions. Axial skeletal muscles are attached to skin, and together these elements form a peculiar elastic cover. A part of muscles of a body strains, resting against hole walls, and the rest of a body is tightened and moves forward at this time. At the same time shortening and lengthening of a body as at a worm, does not occur.
Dwelling area
Legless Amphibia live in tropics and subtropics of Africa, Southeast Asia and Latin America. They live in the lower layers of a forest laying and in the moistened soil, try not to leave far from water. But they do not come into reservoirs as sink.